Package component and forming method thereof

ABSTRACT

A package component and forming method thereof are provided. The package component includes a substrate and a conductive layer. The substrate includes a first surface. The conductive layer is disposed over the first surface. The conductive layer includes a first conductive feature and a second conductive feature. The second conductive feature covers a portion of the first conductive feature. A resistance of the second conductive feature is lower than a resistance of the first conductive feature.

BACKGROUND

The semiconductor industry has experienced rapid growth due to ongoing improvements in the integration density of a variety of electronic components (e.g., transistors, diodes, resistors, capacitors, etc.). Such improvements in integration density have resulted from iterative reduction of minimum feature size, which allows more components to be integrated into a given area. As demand for shrinking electronic devices has grown, a need for smaller and more creative packaging techniques of semiconductor dies has emerged. A printed circuit board (PCB) serves to electrically connect electronic components thereto and mechanically fix them thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the embodiments of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It should be noted that, in accordance with the standard practice in the industry, various structures are not drawn to scale. In fact, the dimensions of the various structures may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 is a flowchart representing a method for forming a package component according to aspects of one or more embodiments of the present disclosure.

FIGS. 2A to 2K are cross-sectional views illustrating a package component at different fabrication stages constructed according to aspects of one or more embodiments of the present disclosure.

FIGS. 3A to 3B are cross-sectional views illustrating a package component at different fabrication stages constructed according to aspects of one or more embodiments of the present disclosure.

FIG. 4 is a flowchart representing a method for forming a package component according to aspects of one or more embodiments of the present disclosure.

FIGS. 5A to 5L) are cross-sectional views illustrating a package component at different fabrication stages constructed according to aspects of one or more embodiments of the present disclosure.

FIG. 6 is a flowchart representing a method for forming a package component according to aspects of one or more embodiments of the present disclosure.

FIGS. 7A to 7C are cross-sectional views illustrating a package component at different fabrication stages constructed according to aspects of one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “over,” “upper,” “on,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

As used herein, although the terms such as “first,” “second” and “third” describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another. The terms such as “first,” “second” and “third” when used herein do not imply a sequence or order unless clearly indicated by the context.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in the respective testing measurements. Also, as used herein, the terms “substantially,” “approximately” or “about” generally mean within a value or range that can be contemplated by people having ordinary skill in the art. Alternatively, the terms “substantially,” “approximately” or “about” mean within an acceptable standard error of the mean when considered by one of ordinary skill in the art. People having ordinary skill in the art can understand that the acceptable standard error may vary according to different technologies. Other than in the operating/working examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for quantities of materials, durations of times, temperatures, operating conditions, ratios of amounts, and the likes thereof disclosed herein should be understood as modified in all instances by the terms “substantially,” “approximately” or “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the present disclosure and attached claims are approximations that can vary as desired. At the very least, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Ranges can be expressed herein as being from one endpoint to another endpoint or between two endpoints. All ranges disclosed herein are inclusive of the endpoints, unless specified otherwise.

A printed circuit board (PCB) serves to electrically connect electronic components to the PCB and mechanically fix the electronic components on the PCB. The PCB includes an insulator and a copper foil adhered to the insulator. One issue with higher frequencies of electrical signals used in PCBs is transmission loss. The transmission loss may be caused by a high resistance of a conductive material of a component (such as the copper foil in the PCB). For example, the electrical signal's higher frequency causes the electrical signal to be transmitted close to the copper foil's surface, leading to a type of conductor loss known as a skin effect. As an electrical current's frequency increases, most of the current flows close to the conductor's surface, resulting in the transmission loss. An approach to mitigate the transmission loss in the PCB is therefore of primary importance.

Some embodiments of the present disclosure provide a package component and a forming method thereof that provides one or more improvements over existing approaches. The present disclosure relates to a package component that includes a conductive layer having a conductive feature with a lower resistance. By forming the conductive layer as introduced below, a transmission loss may be reduced. In addition, the disclosed package component provides better conduction in high-frequency applications (e.g., greater than or substantially equal to 1 GHz). A performance of the package component may be thereby improved.

FIG. 1 is a flowchart representing a method 100 for forming a package component according to aspects of one or more embodiments of the present disclosure. The method 100 for forming the package component includes an operation 102, in which a substrate is provided or received. The method 100 further includes an operation 104, in which a first patterned conductive film is formed over the substrate. The method 100 further includes an operation 106, in which a second conductive film is selectively deposited over the first patterned conductive film to form a conductive layer. In some embodiments, the conductive layer includes the first patterned conductive film and the second conductive film. In some embodiments, a resistance of the second conductive film is lower than a resistance of the first patterned conductive film.

The method is described for a purpose of illustrating concepts of the present disclosure and the description is not intended to limit the present disclosure beyond what is explicitly recited in the claims. Additional operations can be provided before, during, and after the method described above and illustrated in FIG. 1 , and some operations described can be replaced, eliminated, or moved around for additional embodiments of the method.

FIGS. 2A to 2K are cross-sectional views illustrating a package component 200 at different fabrication stages constructed according to aspects of one or more embodiments of the present disclosure.

Referring to FIG. 2A, a substrate 202. (which is sometimes referred to as a core substrate) is provided or received. The respective step is shown as operation 102 of the method 100 in FIG. 1 . The substrate 202 may be an insulating core and may include one or more layers of insulating materials. In some embodiments, the substrate 202 may include a material such as printed circuit board (PCB) material, fiberglass-reinforced resin material, build-up film such as Ajinomoto build-up film (ABF), pre-impregnated composite fiber (prepreg) material, epoxy, molding compound, epoxy molding compound, polymer material such as polytetrafluoroethylene (PTFE) or polyimide, paper, silica filler, glass fiber, non-woven glass fabric, glass, ceramic, other laminates, the like, or combinations thereof. The substrate 202 may be a double-sided copper-clad laminate (CCL) or the like. In alternative embodiments, the substrate 202 is a single-sided copper-clad laminate. The substrate 202 has a first surface 202-1 and a second surface 202-2 opposite to the first surface 207-1.

FIGS. 2B to 2C illustrate the formation of one or more patterned conductive films (also referred to as conductive features) 204 a and 206 a. The respective step is shown as operation 104 of the method 100 in FIG. 1 . Referring to FIG. 2B, one or more conductive films 204′ and 206′ are formed over the substrate 202. The conductive films 204′ and 206′ may be formed onto opposing sides of the substrate 202. For example, the conductive film 204′ is disposed over the first surface 202-1, while the conductive film 206′ is disposed over the second surface 202-2.

The conductive films 204′ and 206′ may be formed using any suitable conductive materials and any suitable deposition processes (e.g., plating, electroless plating, or the like). The conductive films 204′ and 206′ may be one or more layers of copper (Cu), nickel (Ni), aluminum (Al), silver (Ag), gold (Au), cobalt (Co), ruthenium (Ru), palladium (Pd), titanium (Ti), other conductive materials, the like, or a combination thereof laminated or coated onto opposing sides of the substrate 202.

Referring to FIG. 2C, the conductive films 204′ and 206′ are respectively patterned to form the patterned conductive films 204 a and 206 a. The patterned conductive films 204 a and 206 a may be formed using any suitable lithographic materials (e.g., photoresist) and any suitable lithographic processes (e.g., wet chemical etch, or dry etch such as ashing). For example, the lithographic process may include H₂O₂ mixed with FeCl₃, HCl, H₂SO₄ or HNO₃. In some embodiments, one or more hard mask layers (not shown) are respectively formed over the conductive films 204′ and 206′. The hard mask layers are then patterned through patterned photoresists (not shown) to form openings exposing portions of the conductive films 204′ and 206′, respectively. The exposed portions of the conductive films 204′ and 206′ are etched through the openings of the patterned hard mask layers, forming the patterned conductive films 204 a and 206 a.

The patterned conductive film 206 a may include a roughed surface 206 s. The patterned conductive film 206 a further includes a plurality of fractions 206 f forming the roughed surface 206 s, as shown in an enlarged view of a portion of the patterned conductive film 206 a shown in the dotted circle in FIG. 2C. In some embodiments, the fractions 206 f have sharp and regular configurations. In alternative embodiments, the fractions 206 f have rounded and/or irregular configurations. In some embodiments, the fractions 206 f are pillar-like, irregular, micro-branch, or micro-bulge fractions. In some embodiments, the plurality of fractions 206 f are not a designed structure in the manufacturing process, and a dimension of the plurality of fractions 206 f is smaller than a dimension of the patterned conductive film 206 a. The patterned conductive film 204 a may also include a roughed surface similar to the roughed surface 206 s of the patterned conductive film 206 a.

Referring to FIG. 2D, a conductive film 206 b is selectively deposited over the patterned conductive film 206 a to form a conductive layer 206 including the patterned conductive film 206 a and the conductive film 206 b. The respective step is shown as operation 106 of the method 100 in FIG. 1 . In some embodiments, a resistance of the conductive film 206 b is lower than a resistance of the patterned conductive film 206 a. The conductive film 206 b may be one or more layers of graphene, carbon nanotube (CNT), or other conductive materials. A number of the layers of graphene may be selected such that the resulting package component 200 can meet the requirements for enhancement of electrical and thermal conductivity in a high-frequency application. In some embodiments, the number of the layers of the conductive film 206 b is substantially in a range from 1 to 20.

In some embodiments, the conductive film 206 b is formed on the patterned conductive film 206 a by an electroless plating process. For example, an electroless plating bath comprising copper ions is prepared, and graphene flakes may be dispersed in the electroless plating bath. In alternative embodiments, the conductive film 206 b is selectively deposited on the patterned conductive film 206 a by a chemical vapor deposition (CVD) process.

In some embodiments, an exposed surface of the patterned conductive film 206 a may be entirely covered by the conductive film 206 b. In other words, both an upper surface and sidewall surfaces of the patterned conductive film 206 a are covered by the conductive film 206 b. In some embodiments, the conductive film 206 b covers a portion of the patterned conductive film 206 a. In some embodiments, a coverage ratio of the conductive film 206 b over the patterned conductive film 206 a is substantially in a range from about 50% to about 100%. Alternatively, the coverage ratio may be substantially in a range from about 50% to about 80%. The conductive film 206 b may partially cover the upper surface of the patterned conductive film 206 a. For example, some portions of the patterned conductive film 206 a may remain exposed and are not covered by the conductive film 206 b.

In some embodiments, the conductive film 206 b is substantially conformal with respect to a profile of the patterned conductive film 206 a, as shown in an enlarged view of a portion of the patterned conductive film 206 a shown in the dotted circle in FIG. 2D. In other words, the conductive film 206 b is substantially conformal with respect to the roughed surface 206 s of the patterned conductive film 206 a. In some embodiments, a surface roughness (Ra) of the conductive layer 206 is substantially equal to a surface roughness of the patterned conductive film 206 a.

The proposed method for forming the conductive layer 206 provides advantages. In some comparative embodiments where the conductive film 206 b is absent, transmission loss may occur due to the roughened surface 206 s of the patterned conductive film 206 a and high resistance induced by the skin effect. The proposed method for forming the conductive layer 206 includes depositing the conductive film 206 b having a lower resistance over the patterned conductive film 206 a. The conductive film 206 b may provide enhancement of electrical and thermal conductivity. Accordingly, the transmission loss may be reduced, and better conduction in high-frequency applications may be achieved.

FIGS. 2E to 2F illustrate the formation of another substrate 212 and one or more conductive layers 214 and 216. Referring to FIG. 2E, operations similar to those described with reference to FIGS. 2A to 2D can be repeated for forming the substrate 212 and the conductive layers 214 and 216. The substrate 212 may include any suitable insulative materials that are suitable for forming the substrate 202, as set forth above. The conductive layers 214 and 216 may be formed using any suitable conductive materials and any suitable deposition processes that are suitable for forming the conductive layer 206, as set forth above.

The conductive layer 214 may include a conductive film 214 a and a conductive film 214 b. In some embodiments, a resistance of the conductive film 214 b is lower than a resistance of the conductive film 214 a. The conductive layer 216 may include a conductive film 216 a and a conductive film 216 b. In some embodiments, a resistance of the conductive film 216 b is lower than a resistance of the conductive film 216 a. Alternatively or additionally, a material of the conductive film 214 a is same as a material of the conductive film 216 a. In some embodiments, a material of the conductive film 214 b is same as a material of the conductive film 216 b.

Referring to FIG. 2F, one or more via openings 217 may be formed in the substrate 212. The via opening 217 may be formed using any suitable techniques of forming an opening in the substrate 212 (e.g., laser drilling, mechanical drilling, micro drilling, etching, or the like). Additionally, one or more via structures 218 may be formed in the via openings 217. The via structure 218 is located on and extends along a surface of the via opening 217. The via structure 218 extends through the substrate 212 to physically and electrically connect the conductive layers 214 and 216. The via structure 218 includes a conductive material. The conductive material comprises a metal (e.g., copper, titanium, tungsten, aluminum, alloys thereof, combinations thereof, or the like) and may be formed by plating (e.g., electroplating or electroless plating, or the like). In some embodiments, a material of the via structure 218 is same as the material of the conductive film 214 a or the conductive film 216 a.

In some embodiments, an upper surface of the via structure 218 is substantially coplanar with an upper surface of the conductive film 214 a, In some embodiments, a bottom surface of the via structure 218 is substantially coplanar with a bottom surface of the conductive film 214 b, Alternatively or additionally, the via structure 218 is separated from the conductive film 214 b or 216 b. In some alternative embodiments, the upper surface of the via structure 218 is substantially coplanar with an upper surface of the conductive film 214 b. In some alternative embodiments, the bottom surface of the via structure 218 is substantially coplanar with a bottom surface of the conductive film 214 b. Additionally, the via structure 218 may be in direct physical contact with a sidewall of the conductive film 214 b or 216 b.

In some embodiments, the via structure 218 has a hollow shape. In other words, the via structure 218 has an inner surface exposed to an environment. A via hole dimension D1 of the via structure 218 and a dimension D2 of the conductive film 214 a are selected such that the resulting package component 200 can meet the requirements for accelerating data transmission and/or decreasing capacitance. In some embodiments, the via hole dimension D1 is less than or substantially equal to 0.2 mm (or 8 mil), and the dimension D2 is less than or substantially equal to 0.13 mm (or 5 mil). A ratio of the dimension D2 to the via hole dimension D1 is selected such that the resulting package component 200 can meet the requirements of high-frequency applications. In some embodiments, the ratio of the dimension D2 to the via hole dimension D1 is substantially in a range from about 0.15 to about 3.

A ratio of a thickness D3 of the via structure 218 to the via hole dimension D1 is selected such that the resulting package component 200 can meet the requirements of high-frequency applications. In some embodiments, the ratio of the thickness D3 to the via hole dimension D1 is substantially in a range from about 0.1 to about 0.25. A thickness D4 of the conductive film 214 a is selected such that the resulting package component 200 can meet the requirements of high-frequency applications. In some embodiments, the thickness D4 is substantially in a range from about 0.0175 mm to about 0.035 mm. A ratio of the dimension D2 of the conductive film 214 a to the thickness D4 of the conductive film 214 a is selected such that the resulting package component 200 can meet the requirements of high-frequency applications. In some embodiments, the ratio of the dimension D2 to the thickness D4 is substantially in a range from about 0.5 to about 8.

In some alternative embodiments, after the forming of the via structure 218 along sidewalls of the via opening 217, the via opening 217 may then be filled with a dielectric through via core (not shown) using a material such as a molding material, epoxy, an epoxy molding compound, a resin, materials including monomers or oligomers, such as acrylated urethanes, rubber-modified acrylated epoxy resins, or multifunctional monomers, the like, or a combination thereof. In some embodiments, the dielectric through via core may include pigments or dyes (e.g., for color), or other fillers and additives that modify rheology, improve adhesion, or affect other properties of the dielectric through via core. The dielectric through via core may be formed using, e.g., a spin-on process or another process. In some embodiments, the conductive material for forming the via structure 218 may completely fill the via opening 217, omitting the dielectric through via core.

FIG. 2G illustrates the formation of another substrate 222, one or more conductive layers 224 and one or more conductive films 226 a. Referring to FIG. 2G, operations similar to those described with reference to FIGS. 2A to 2D can be repeated for forming the substrate 222, the conductive layer 224 and the conductive film 226 a. The substrate 222 may include any suitable insulative materials that are suitable for forming the substrate 202, as set forth above.

The conductive layer 224 and the conductive film 226 a may respectively be formed using any suitable conductive materials and any suitable deposition processes that are suitable for forming the conductive layer 206 and the patterned conductive film 204 a, as set forth above. The conductive layer 224 may include a patterned conductive film 224 a and a conductive film 224 b. In some embodiments, a resistance of the conductive film 224 b is lower than a resistance of the patterned conductive film 224 a. Alternatively or additionally, a material of the patterned conductive film 224 a is same as a material of the conductive film 226 a.

Referring to FIG. 2H, the substrate 212 is attached to the substrate 202. In some embodiments, the substrate 212 is attached to the substrate 202 by a dielectric layer 232. The dielectric layer 232 may include one or more layers of insulating materials. In some embodiments, the dielectric layer 232 may include glass fiber weave/cloth impregnated with a resin bonding agent. The dielectric layer 232 may be referred to as an encapsulant, a prepreg, an adhesive layer or a glue layer. In some embodiments, the dielectric layer 232 surrounds a lateral sidewall of the conductive film 206 b or 214 b. In some embodiments, the via structure 218 is electrically isolated from the conductive layer 206. The via structure 218 may be electrically isolated from the conductive layer 206 by the dielectric layer 232.

Referring to FIG. 2I, the substrate 222 is attached to the substrate 212. In some embodiments, the substrate 222 is attached to the substrate 212 by a dielectric layer 234. The dielectric layer 234 may include any suitable insulative materials that are suitable for forming the dielectric layer 232, as set forth above.

Referring to FIG. 2J, a conductive film 204 b is deposited over the patterned conductive film 204 a to form a conductive layer 204 including the patterned conductive film 204 a and the conductive film 204 b. Additionally, a conductive film 226 b is deposited over the conductive film 226 a to form a conductive layer 226 including the conductive film 226 a and the conductive film 226 b. In some embodiments, a resistance of the conductive film 204 b is lower than a resistance of the patterned conductive film 204 a. Alternatively or additionally, a resistance of the conductive film 226 b is lower than a resistance of the conductive film 226 a. The conductive films 204 b and 226 b may be formed using any suitable conductive materials and any suitable deposition processes that are suitable for forming the conductive film 206 b, as set forth above.

Referring to FIG. 2K, one or more through vias (also referred to as through via openings) 241 and 243 may be formed. The through vias 241 and 243 may penetrate through the substrates 202, 212 and 222. In some embodiments, the through vias 241 and 243 further penetrate through one or more conductive layers. For example, the through via 241 penetrates through the conductive layers 204, 224 and 226. Additionally, the through via 243 penetrates through the conductive layers 204 and 226. The through vias 241 and 243 may be formed using any suitable techniques of forming openings in the substrates 202, 212 and 222 (e.g., laser drilling, mechanical drilling, etching, or the like).

Additionally, one or more through via structures 242 and 244 may respectively be formed in the through vias 241 and 243, The through via structure 242 is located on and extends along a surface of the through via 241. The through via structure 242 extends through the substrates 202, 212 and 222 to physically and electrically couple the conductive layers 204, 224 and 226. The through via structure 244 is located on and extends along a surface of the through via 243. The through via structure 244 extends through the substrates 202, 212 and 222 to physically and electrically couple the conductive layers 204 and 226. The through via structures 242 and 244 include conductive materials. The conductive materials comprise a metal (e.g., copper, titanium, tungsten, aluminum, alloys thereof, combinations thereof, or the like) and may be formed by plating (e.g., electroplating or electroless plating, or the like). In some embodiments, the material of the through via structures 242 and 244 is same as the material of the patterned conductive film 204 a.

In some embodiments, an upper surface of the through via structure 242 or 244 is substantially coplanar with an upper surface of the conductive film 226 a. Alternatively or additionally, a bottom surface of the through via structure 242 or 244 is substantially coplanar with a bottom surface of the patterned conductive film 204 a. In some alternative embodiments, the upper surface of the through via structure 242 or 244 is substantially coplanar with an upper surface of the conductive film 226 b. Alternatively or additionally, the bottom surface of the through via structure 242 or 244 is substantially coplanar with a bottom surface of the conductive film 204 b.

In some embodiments, the through via structures 242 and 244 have a hollow shape. In other words, the through via structures 242 and 244 respectively have an inner surface exposed to an environment. A via hole dimension D5 of the via structure 242 (or 244) may be less than or substantially equal to 0.2 mm. A ratio of a depth. D6 of the via structure 242 (or 244) to the via hole dimension D5 is selected such that the resulting package component 200 can meet the requirements of high-frequency applications. In some embodiments, the ratio of the depth D6 to the via hole dimension D5 is substantially in a range from about 2 to about 8.

Still referring to FIG. 2K, one or more via openings 227 may be formed in the substrate 222. The via opening 227 may be formed using any suitable techniques of forming an opening in the substrate 222. Additionally, one or more via structures 228 may be formed in the via openings 227. The via structure 228 is located on and extends along a surface of the via opening 227. The via structure 228 extends through the substrate 222 to physically and electrically couple the conductive layers 224 and 226. The via structure 228 includes a conductive material. The conductive material comprises a metal (e.g., copper, titanium, tungsten, aluminum, alloys thereof, combinations thereof, or the like) and may be formed by plating (e.g., electroplating or electroless plating, or the like). In some embodiments, the material of the via structure 228 is same as the material of the patterned conductive film 224 a or the conductive film 226 a.

A package component 200 is thus formed. The proposed method for forming the package component 200 provides advantages. The proposed method for forming the package component 200 includes forming a conductive layer including a conductive film having a lower resistance over another conductive film having a higher resistance. The conductive film with the lower resistance may provide enhancement of electrical and thermal conductivity. Accordingly, transmission loss in the package component may be reduced, and better conduction of the package component in high-frequency applications may be achieved.

The package component 200 includes three substrates 202, 212, and 222 and six conductive layers 204, 206, 214, 216, 224 and 226. The package components of the present disclosure are not limited to the above-mentioned embodiments and may have other different embodiments. A number of the conductive layers in the package component 200 is selected such that the resulting package component 200 can meet requirements of high-frequency applications. In some embodiments, the number of the conductive layers in the package component 200 is in a range from 4 to 14.

The structures of the present disclosure are not limited to the above-mentioned embodiments and may have other different embodiments. To simplify the description and for convenience of comparison between each of the embodiments of the present disclosure, identical (or like) components in each of the following embodiments are marked with identical (or like) numerals. For making it easier to compare differences between the embodiments, the following description will detail dissimilarities among different embodiments, while identical features, values and definitions will not be repeated.

FIGS. 3A to 3B are cross-sectional views illustrating a package component 300 at different fabrication stages constructed according to aspects of one or more embodiments of the present disclosure. FIGS. 3A to 3B illustrate an alternative approach to obtaining via structures.

Referring to FIG. 3A, subsequent to the operations described with reference to FIG. 2I, one or more through vias 341 and 343 and one or more via openings 327 may be formed. Additionally, one or more conductive films 342 a, 344 a and 328 a may respectively be formed in the through vias 341 and 343 and the via openings 327. In some embodiments, a material of the conductive films 342 a, 344 a and 328 a is same as the material of the conductive film 226 a.

Referring to FIG. 3B, a conductive film 204 b is deposited over the patterned conductive film 204 a to form a conductive layer 204, and a conductive film 226 b is deposited over the conductive film 226 a to form a conductive layer 226. Additionally, one or more conductive films 342 b, 344 b and 328 b are selectively deposited over the conductive films 342 a, 344 a and 328 a to form through via structures 342 and 344 and a via structure 328. In some embodiments, a resistance of the conductive films 342 b, 344 b and 328 b is lower than a resistance of the conductive films 342 a, 344 a and 328 a, In some embodiments, a material of the conductive films 342 b, 344 b and 328 b is same as the material of the conductive film 206 b. The conductive films 342 b, 344 b and 328 b may be formed using any suitable conductive materials and any suitable deposition processes that are suitable for forming the conductive film 206 h, as set forth above.

In some embodiments, an exposed surface of the conductive film 342 a, 344 a or 328 a may be entirely covered by the conductive film 342 b, 344 b or 328 b. In other words, both upper surfaces and sidewall surfaces of the conductive film 342 a, 344 a or 328 a are covered by the conductive film 342 b, 344 b or 328 b. In some embodiments, a coverage ratio of the conductive film 342 h, 344 b or 328 b over the conductive film 342 a, 344 a or 328 a is substantially in a range from about 50% to about 100%. In some embodiments, the conductive film 342 b, 344 b or 328 b partially covers the conductive film 342 a, 344 a or 328 a, respectively. In other words, some portions of the conductive film 342 a, 344 a or 328 a may remain exposed and are not covered by the conductive film 342 b, 344 b or 328 b.

In some embodiments, the conductive film 342 b, 344 b or 328 b is substantially conformal with respect to a profile of the conductive film 342 a, 344 a or 328 a. In some embodiments, the conductive film 342 a, 344 a or 328 a has a roughed surface similar to the roughed surface 206 s (see FIG. 2D) of the patterned conductive film 206 a. In some embodiments, a surface roughness of the through via structure 342 or 344 is substantially equal to a surface roughness of the conductive film 342 a or 344 a. Alternatively or additionally, a surface roughness of the via structure 328 is substantially equal to a surface roughness of the conductive film 328 a. In some embodiments, the conductive film 342 b or 344 b is separated from the conductive layers 204, 224 or 226 by the conductive film 342 a or 344 a.

In some embodiments, the through via structures 342 and 344 have a hollow shape. In other words, the through via structures 342 and 344 respectively have an inner surface exposed to an environment. In some embodiments, the conductive film 342 b (or 344 b) having the lower resistance is disposed close to the inner surface, while the conductive film 342 a (or 344 a) is disposed distal to the inner surface. The via structure 328 may have a hollow shape. In other words, the via structure 328 has an inner surface exposed to an environment. In some embodiments, the conductive film 328 b having the lower resistance is disposed close to the inner surface, while the conductive film 328 a is disposed distal to the inner surface.

A package component 300 is thus formed. The proposed method for forming the package component 300 provides advantages. The proposed method for forming the package component 300 includes forming a through via structure (or a via structure) including a conductive film having a lower resistance over another conductive film having a higher resistance. The conductive film with the lower resistance may provide enhancement of electrical and thermal conductivity. Accordingly, transmission loss in the package component may be reduced, and better conduction of the package component in high-frequency applications may be achieved,

FIG. 4 is a flowchart representing a method 400 for forming a package component according to aspects of one or more embodiments of the present disclosure. The method 400 for forming the package component includes an operation 402, in which a substrate is provided or received. The method 400 further includes an operation 404, in which a conductive layer is formed over the substrate. In some embodiments, the conductive layer includes a first conductive film and a second conductive film. In some embodiments, a resistance of the second conductive film is lower than a resistance of the first conductive film. The method 400 further includes an operation 406, in which the conductive layer is patterned.

The method is described for a purpose of illustrating concepts of the present disclosure and the description is not intended to limit the present disclosure beyond what is explicitly recited in the claims. Additional operations can be provided before, during, and after the method described above and illustrated in FIG. 4 , and sonic operations described can be replaced, eliminated, or moved around for additional embodiments of the method.

FIGS. 5A to 51 ) are cross-sectional views illustrating a package component 500 at different fabrication stages constructed according to aspects of one or more embodiments of the present disclosure.

Referring to FIG. 5A, a substrate 502 is provided or received. The respective step is shown as operation 402 of the method 400 in FIG. 4 . The substrate 502 may be an insulating core and may include one or more layers of insulating materials. The substrate 502 may be formed using any suitable insulating materials that are suitable for forming the substrate 202, as set forth above. The substrate 502 has a first surface 502-1 and a second surface 502-2 opposite to the first surface.

Referring to FIG. 5B, FIG. 5B illustrates the formation of one or more conductive layers 504 and 506 over the substrate 502. The respective step is shown as operation 404 of the method 400 in FIG. 4 . The conductive layers 504 and 506 may be formed onto opposing sides of the substrate 502. For example, the conductive layer 504 is disposed over the first surface 502-1, while the conductive layer 506 is disposed over the second surface 502-2.

The conductive layer 504 includes a conductive film 504 a and a conductive film 504 b. The conductive film 504 a directly contacts the first surface 502-1, while the conductive film 504 b is separated from the first surface 502-1 by the conductive film 504 a. The conductive layer 506 includes a conductive film 506 a, and a conductive film 506 b. The conductive film 506 a directly contacts the second surface 502-2, while the conductive film 506 b is separated from the second surface 502-2 by the conductive film 506 a. In some embodiments, a resistance of the conductive film 504 b or 506 b is lower than a resistance of the conductive film 504 a or 506 a.

The conductive films 504 a/506 a and 504 b/506 b may include any suitable conductive materials that are suitable for the conductive films 204 a/204 b or 206 a/206 b, as set forth above, For example, a material of the conductive film 504 b (or 506 b) may be graphene. A number of layers of the graphene is selected such that the resulting package component 500 can meet requirements of enhancement of electrical and thermal conductivity in high-frequency applications. In some embodiments, the number of the layers of the material of the conductive film 504 b (or 506 b) is substantially in a range from 1 to 20.

In some embodiments, the conductive films 504 b and 506 b are respectively formed on the conductive films 504 a and 506 a by a CVD process. In some alternative embodiments, the conductive films 504 b and 506 b are respectively formed on the conductive films 504 a and 506 a, by a roll-to-roll process. For example, the conductive films 504 b and 506 b may be prepared in an electrochemically exfoliated process and are respectively formed on the conductive films 504 a and 506 a by a roll-to-roll fabrication process. In some embodiments, a solution of the conductive film 504 b or 506 b (e.g., a solution comprising electrochemically exfoliated graphene) is prepared, and the solution is added dropwise into a water bath. A roll-sheet of the conductive film 504 a or 504 b may be immersed in the water bath. Next, the roll-sheet of the conductive film 504 a or 504 b is slowly pulled out by rotating a roller from the water bath with the conductive film 504 b or 504 b attached.

In some embodiments, an exposed surface (e.g., an upper surface) of the conductive film 504 a or 506 a may respectively be entirely covered by the conductive film 504 b or 506 b. In alternative embodiments, the exposed surface of the conductive film 504 a or 506 a may respectively be partially covered by the conductive film 504 b or 506 b. The conductive films 504 b or 506 b may be partially cladded on the conductive films 504 a or 506 a, respectively. In other words, the conductive films 504 b or 506 b may partially cover the upper surface of the conductive films 504 a or 506 a. In some embodiments, a coverage ratio of the conductive film 504 b or 506 b over the conductive film 504 a or 506 a is substantially in a range from about 5% to about 95%. In other words, some portions of the conductive film 504 a or 506 a may remain exposed and are not covered by the conductive film 504 b or 506 b.

In some embodiments, the conductive film 504 b or 506 b is substantially conformal with respect to a profile of the conductive film 504 a or 506 a, as shown in an enlarged view of a portion of the conductive films 506 a and 506 b shown in the dotted circle in FIG. 513 , The conductive film 506 a may include a roughed surface 506 s. The conductive film 506 a further includes a plurality of fractions 506 f forming the roughed surface 506 s, The fractions 506 f may have configurations similar to those of the fractions 206 f, as set forth above. In some embodiments, the fractions 506 f are not a designed structure in the manufacturing process, and a dimension of the fractions 506 f is smaller than a dimension of the conductive film 506 a. In some embodiments, the conductive film 504 a may include a roughed surface similar to the roughed surface 506 s of the conductive film 506 a. In some embodiments, the conductive film 506 b is substantially conformal with respect to the roughed surface 506 s of the conductive film 506 a. In some embodiments, a surface roughness of the conductive layer 506 is substantially equal to a surface roughness of the conductive film 506 a.

Referring to FIG. 5C, the conductive layers 504 and 506 are patterned. The respective step is shown as operation 406 of the method 400 in FIG. 4 . The conductive layers 504 and 506 may be patterned using any suitable lithographic materials (e.g., photoresist) and any suitable lithographic processes (e.g., wet chemical etch, dry etch such as ashing), as set forth above.

Referring to FIG. 5C, FIG. 5D illustrates a formation of the package component 500. The package component 500 may include the substrate 502 and the conductive layers 504 and 506. The package component 500 may further include a substrate 512, conductive layers 514 and 516, a substrate 522, and conductive layers 524 and 526. Operations similar to those described with reference to FIGS. 5A to 5C can be repeated for forming the substrates 512 and 522 and the conductive layers 514, 516, 524 and 526, In some embodiments, operations similar to those described with reference to FIG. 2F can be repeated for forming a via structure 518 in the substrate 512. The via structure 518 may include any suitable conductive materials that are suitable for forming the via structures 218, as set forth above.

Alternatively or additionally, operations similar to those described with reference to FIGS. 2H to 2I can be repeated for attaching the substrate 512 to the substrate 502 by a dielectric layer 532, and attaching the substrate 522 to the substrate 512 by a dielectric layer 534. The dielectric layers 532 and 534 may include any suitable insulative materials that are suitable for forming the dielectric layer 232 as set forth above. In some embodiments, the dielectric layer 532 surrounds a lateral sidewall of the conductive film 506 b or 514 b. In some embodiments, the dielectric layer 532 further surrounds a lateral sidewall of the conductive film 506 a or 514 a.

In some embodiments, operations similar to those described with reference to FIG. 2K can be repeated for forming through via structures 542 and 544 and a via structure 528. The through via structures 542 and 544 and the via structure 528 may include any suitable conductive materials that are suitable for forming the through via structures 242 and 244 and the via structure 228, as set forth above.

The proposed method for forming the package component 500 provides advantages. The proposed method for forming the package component 500 includes forming a conductive layer including a conductive film having a lower resistance over another conductive film having a higher resistance. The conductive film with the lower resistance may provide enhancement of electrical and thermal conductivity. Accordingly, transmission loss in the package component may be reduced, and better conduction of the package component in high-frequency applications may be achieved.

FIG. 6 is a flowchart representing a method 600 for forming a package component according to aspects of one or more embodiments of the present disclosure. The method 600 for forming the package component includes an operation 602, in which a substrate is provided or received. The method 600 further includes an operation 604, in which a conductive layer is formed over the substrate. In some embodiments, the conductive layer includes a first material and a second material. In some embodiments, a resistance of the second material is lower than a resistance of the first material. The method 600 further includes an operation 606, in which the conductive layer is patterned.

The method is described for a purpose of illustrating concepts of the present disclosure and the description is not intended to limit the present disclosure beyond what is explicitly recited in the claims. Additional operations can be provided before, during, and after the method described above and illustrated in FIG. 6 , and some operations described can be replaced, eliminated, or moved around for additional embodiments of the method.

FIGS. 7A to 7C are cross-sectional views illustrating a package component 700 at different fabrication stages constructed according to aspects of one or more embodiments of the present disclosure.

Referring to FIG. 7A, a substrate 702 is provided or received. The respective step is shown as operation 602 of the method 600 in FIG. 6 . The substrate 702 may be an insulating core and may include one or more layers of insulating materials. The substrate 702 may be formed using any suitable insulating materials that are suitable for forming the substrate 202, as set forth above.

FIG. 7A further illustrates formation of one or more conductive layers 704 and 706 over the substrate 702. The respective step is shown as operation 604 of the method 600 in FIG. 6 . The conductive layers 704 and 706 may be formed onto opposing sides of the substrate 702. The conductive layer 704 includes a conductive film 704 a and a conductive film 704 b. The conductive layer 706 includes a conductive film 706 a and a conductive film 706 b. In some embodiments, a resistance of the conductive film 704 h or 706 b is lower than a resistance of the conductive film 704 a or 706 a.

In some embodiments, the conductive film 704 b (or 706 b) may be comprised of microstructures dispersed or inserted in the conductive film 704 a (or 706 a). The conductive film 704 b (or 706 b) may also be comprised of flakes dispersed or inserted in the conductive film 704 a (or 706 a). A dimension of the microstructure (or the flake) is selected such that the resulting package component 700 can meet requirements for enhancement of electrical and thermal conductivity in high-frequency applications. In some embodiments, the dimension of the microstructure (or the flake) is substantially in a range from one-fiftieth of a minimum width of the conductive layer 704 (or 706) to one-half of the minimum width of the conductive layer 704 (or 706).

The conductive films 704 a/706 a and 704 b/706 b may include any suitable conductive materials that are suitable for the conductive films 204 a/204 b or 206 a/206 b, as set forth above. For example, the material of the conductive film 704 b (or 706 b) may be graphene. A number of layers of the graphene is selected such that the resulting package component 700 can meet the requirements for the enhancement of electrical and thermal conductivity in high-frequency applications. In some embodiments, the number of the layers of the material of the conductive film 704 b (or 706 b) is substantially in a range from 1 to 20.

In some embodiments, the conductive layers 704 and 706 are formed by an electrolytic formation process. For example, a solution including the material of the conductive film 704 a (or 706 a) and the material of the conductive film 704 b (or 706 b) is prepared. A rotating electrode may be immersed into the solution. Next, a foil of the conductive layer 704 (or 706) is slowly pulled out from the solution with the material of the conductive film 704 b (or 706 b) dispersed in the material of the conductive film 704 a (or 706 a), In some embodiments, a volume ratio of the material of the conductive film 704 b (or 706 b) in the conductive layer 704 (or 706) is substantially in a range from about 0.01% to about 80%. In some embodiments, the solution may be a copper sulfate plating bath including copper ions and graphene flakes. In alternative embodiments, the solution may be a copper sulfate plating bath including copper ions and carbon nanotube fibers.

In some embodiments, the conductive layer 706 has a roughed surface 706 s, as shown in an enlarged view of a portion of the conductive layer 706 shown in the dotted circle in FIG. 7A. The conductive layer 706 further includes a plurality of fractions 706 f forming the roughed surface 706 s. The fractions 706 f may have configurations similar to those of the fractions 206 f, as set forth above. In some embodiments, the fractions 706 f are not a designed structure in the manufacturing process, and a dimension of the fractions 706 f is smaller than a dimension of the conductive layer 706. In some embodiments, the material of the conductive film 706 b is disposed adjacent to the fractions 706 f. In alternative embodiments, the material of the conductive film 706 b is at least partially disposed in the fractions 706 f In some embodiments, the material of the conductive film 706 b protrudes from the roughed surface 706 s. The conductive layer 704 may include a roughed surface similar to the roughed surface 706 s of the conductive layer 706.

Referring to FIG. 7B, the conductive layers 704 and 706 are patterned. The respective step is shown as operation 606 of the method 600 in FIG. 6 . The conductive layers 704 and 706 may be patterned using any suitable lithographic materials (e.g., photoresist) and any suitable lithographic processes (e.g., wet chemical etch, or dry etch such as ashing), as set forth above,

Referring to FIG. 7C, FIG. 7C illustrates a formation of the package component 700. The package component 700 may include the substrate 702 and the conductive layers 704 and 706. The package component 700 may further include a substrate 712, conductive layers 714 and 716, a substrate 722, and conductive layers 724 and 726. Operations similar to those described with reference to FIGS. 7A to 7B can be repeated for forming the substrates 712 and 722 and the conductive layers 714, 716, 724 and 726. In some embodiments, operations similar to those described with reference to FIG. 2F can be repeated for forming a via structure 718 in the substrate 712. The via structure 718 may include any suitable conductive materials that are suitable for forming the via structures 218, as set forth above.

Alternatively or additionally, operations similar to those described with reference to FIGS. 2H to 2I can be repeated for attaching the substrate 712 to the substrate 702 by a dielectric layer 732, and attaching the substrate 722 to the substrate 712 by a dielectric layer 734. The dielectric layers 732 and 734 may include any suitable insulative materials that are suitable for forming the dielectric layer 232, as set forth above.

In some embodiments, operations similar to those described with reference to FIG. 2K can be repeated for forming through via structures 742 and 744 and a via structure 728. The through via structures 742 and 744 and the via structure 728 may include any suitable conductive materials that are suitable for forming the through via structures 242 and 244 and the via structure 228, as set forth above.

The proposed method for forming the package component 700 provides advantages. The proposed method for forming the package component 700 includes forming a conductive layer including materials having different resistances. The material with lower resistance may provide enhancement of electrical and thermal conductivity. Accordingly, transmission loss in the package component may be reduced, and better conduction of the package component in high-frequency applications may be achieved.

In accordance with some embodiments of the present disclosure, a package component is provided. The package component includes a substrate and a first conductive layer. The substrate includes a first surface and a second surface opposite to the first surface. The first conductive layer is disposed over the first surface. The first conductive layer includes a first conductive feature and a second conductive feature. The second conductive feature covers a portion of the first conductive feature. A resistance of the second conductive feature is lower than a resistance of the first conductive feature.

In accordance with some embodiments of the present disclosure, a package component is provided. The package component includes a first substrate, a first conductive layer, a second substrate and an encapsulant. The first substrate has a first surface and a second surface opposite to the first surface. The first conductive layer is disposed over the second surface of the first substrate. The first conductive layer comprises a first conductive feature and a second conductive feature over the first conductive feature. A resistance of the first conductive feature is greater than a resistance of the second conductive feature. The second substrate is disposed over the second surface of the first substrate. The second substrate has a third surface and a fourth surface opposite to the third surface, and the third surface faces the second surface. The encapsulant is disposed between the first substrate and the second substrate. The encapsulant surrounds a lateral sidewall of the second conductive feature.

In accordance with some embodiments of the present disclosure, a method of forming a package component is provided. The method includes following operations. A substrate is provided or received. A first patterned conductive film is formed over the substrate. A second conductive film is selectively deposited over the first patterned conductive film to form a conductive layer comprising the first patterned conductive film and the second conductive film. A resistance of the second conductive film is lower than a resistance of the first patterned conductive film.

The foregoing outlines structures of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. 

What is claimed is:
 1. A package component, comprising: a substrate comprising a first surface and a second surface opposite to the first surface; and a first conductive layer over the first surface, the first conductive layer comprising: a first conductive feature; and a second conductive feature over the first conductive feature, wherein the second conductive feature covers a portion of the first conductive feature, and a resistance of the second conductive feature is lower than a resistance of the first conductive feature.
 2. The package component of claim 1, wherein the first conductive feature directly contacts the first surface, and the second conductive feature is separated from the first surface by the first conductive feature.
 3. The package component of claim 1, wherein the second conductive feature entirely covers an upper surface and sidewall surfaces of the first conductive feature.
 4. The package component of claim 1, wherein a coverage ratio of the second conductive feature over the first conductive feature is substantially in a range from about 50% to about 100%.
 5. The package component of claim 1, wherein a coverage ratio of the second conductive feature over the first conductive feature is substantially in a range from about 5% to about 95%.
 6. The package component of claim 1, wherein the substrate comprises a single-sided or a double-sided copper-clad laminate.
 7. The package component of claim 1, further comprising: a second conductive layer over the second surface.
 8. The package component of claim 7, further comprising: a via structure penetrating through the substrate and electrically connecting the second conductive layer to the first conductive layer.
 9. The package component of claim 8, wherein the via structure has an inner surface exposed to an environment.
 10. The package component of claim 8, wherein the via structure comprises: a third conductive feature contacting the first conductive layer and the second conductive layer; and a fourth conductive feature over the third conductive feature, wherein the fourth conductive feature is separated from the second conductive layer and the first conductive layer by the third conductive feature, wherein a resistance of the fourth conductive feature is lower than a resistance of the third conductive feature.
 11. A package component, comprising: a first substrate having a first surface and a second surface opposite to the first surface; a first conductive layer over the second surface of the first substrate, the first conductive layer comprising a first conductive feature and a second conductive feature over the first conductive feature, wherein a resistance of the first conductive feature is greater than a resistance of the second conductive feature; a second substrate over the second surface of the first substrate, wherein the second substrate has a third surface and a fourth surface opposite to the third surface, and the third surface faces the second surface; and an encapsulant disposed between the first substrate and the second substrate, wherein the encapsulant surrounds a lateral sidewall of the second conductive feature.
 12. The package component of claim 11, wherein the encapsulant further surrounds a lateral sidewall of the first conductive feature.
 13. The package component of claim 11, further comprising: a second conductive layer over the third surface of the second substrate.
 14. The package component of claim 13, further comprising: a through via structure penetrating through the first substrate and the second substrate, and electrically connecting the first conductive layer to the second conductive layer.
 15. The package component of claim 14, wherein a ratio of a depth of the through via structure to a via hole dimension of the through via structure is substantially in a range from about 2 to about
 8. 16. The package component of claim 13, further comprising: a via structure penetrating through the second substrate and electrically connected to the second conductive layer, wherein the via structure is electrically isolated from the first conductive layer.
 17. The package component of claim 16, wherein a via hole dimension of the via structure is less than or substantially equal to 0.2 mm.
 18. A method for forming a package component, comprising: providing or receiving a substrate; forming a first patterned conductive film over the substrate; and selectively depositing a second conductive film over the first patterned conductive film to form a conductive layer comprising the first patterned conductive film and the second conductive film, wherein a resistance of the second conductive film is lower than a resistance of the first patterned conductive film.
 19. The method of claim 18, wherein a surface roughness (Ra) of the conductive layer is substantially equal to a surface roughness of the first patterned conductive film.
 20. The method of claim 18, further comprising: forming a through via penetrating through the substrate; forming a third conductive film in the through via; and forming a fourth conductive film covering an exposed surface of the third conductive film to form a through via structure comprising the third conductive film and the fourth conductive film, wherein a resistance of the fourth conductive film is lower than a resistance of the third conductive film. 